First, a long time ago, he sent in a photograph of the fringes of the two Anderson square rotating prisms (See "Amateur Telescope Making," page 200, bottom line, and Fig. 19). From it you may judge for yourself what sort of workmanship he puts up. In this picture (at left, below), the top fringes represent the top of the prisms against a strip flat. The edge of the latter shows just below these. The bottom set of fringes represents reflections on the bottom surface of a six-inch flat on which the prisms rested, and are a combination of the two, badly distorted. The test shows that the prisms are flat but are off in thickness by one fringe. "Making these prisms," Prescott wrote, "is one hell of a job." But he added, "I am getting quite a kick out of this business."

Some time later he wrote, "The unit that carries the brains of the outfit is no in process of getting the works. This unit is an intricate proposition, believe me, and one that I shall have some trouble with. The mirrors are both six-inch flats, instead of three inch and four-inch, as called for."

A few months later he sent in a picture of the said "brains" of the thing, all finished, and isn't it a beauty!

By May of the present year we again heard from him, when he had got the job far enough advanced to do some preliminary playing with it. He wrote, "You really can't appreciate the kick I got out of it the first time I brought out the sun's disk. I did not have a motor at hand and so wound some string on the rotating prism shaft, gave her a spin, and there was Old Sol in all his glory. Boy, I'll get the best of the devil yet! "

On June 17 we received an enthusiastic postal card which we reproduce in these columns-the spectrohelioscope was then in regular use.

Finally, on July 20, we heard:

"Enclosed are the photographs of the spectrohelioscope, as set op and 'a'wukkin'. Total cash outlay 42 dollars, so one should not be frightened by the financial aspect. Somehow the Lord will provide the grating.

"This job is something that offers a true test for dyed-in-the-wool amateurism-13 surfaces optically flat to 1/4 wave; two 3-inch, 13-foot focus spherical mirrors, and one convex surface to figure, with plenty of machine shop work thrown in.

"The making of the flats and square prism is the most interesting work of all. Here one deals with measurements of the order of a few millionths of an inch, an you are dead sure if successful, that no professional optical worker can do better. Pride in accomplishment gets in its work here, and repays you in full.

"The real kick comes in using the instrument. The first prominence you see will blow you down. The first one I saw stood out from the limb of the sun like two gigantic willow trees in a gale of wind. In 15 minutes they were gone, only to reappear a short time afterwards. There is action on such a gigantic scale that earthly spectacles are pygmified. Right now Satan is stoking up the fires again and many spots and prominences will appear. Build one of these machines and break into a study that is still in the diaper stage.

"I cannot yet report very much about this outfit, as all I have been able to see thus far are prominences, except one small spot. It works O.K. however."

Smooth as Prescott's workmanship appears in the illustrations, these do not do it half justice. The original photographs show his instruments to be equal in grade and quality and finish to professional instrument makers' work. We are still mystified, however, about the grating. Did "the Lord" really provide one-or possibly help him who . . . ?

Another spectrohelioscope is being brewed in Chicago, or rather in Wilmette, Illinois, a Chicago suburb, by A. Klapperich, 412 Central Avenue, and may be finished before this account appears.

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